Die set



June 24, 1947. e. o. CONNER DIE SET 3 Sheets-Sheet 1 Filed Jan. 22, 1944IN VEN TOR. 60) 0' CON/V5}? A TTOENEYS June 24, 1947. G. o. CONNER DIESET Filed Jan. 22, 1944 3 Sheets-Sheet 2 IN VEN TOR.

A TTOFENEYS June 24, 1947. e. o. CONNER DIE SET Filed Jan. 22, 1944 3Sheets-Sheet 5 INVENTOR. 60) 0- CO/V/VE/P Patented June 24, 1947 UNITEDSTATES PATENT OFFICE DIE SET Guy 0. Conner, Redford, Ohio ApplicationJanuary 22, 1944, Serial No. 519,284

22 Claims.

This invention relates to improvements in punch presses and moreparticularly to improvements in die sets for punch presses or the like.

As is well known to those versed in the art. certain classes of articlesare manufactured by the use of presses. These presses usually employ abase which holds a die and a reciprocable plunger which carries anotherdie or punch that mates with that of the base and the sheet metal stockis placed between the two dies, which, when they come together, eitherstamp out or form the stock to the desired shape. The dies, being theparts where most wear occurs. are the parts that are most often changed;also because of the various types of parts produced, different dies maybe substituted to form the desired type of part.

It has been common practice to provide a support for the dies. called adie set which is also removable but which is of a. predetermined form tolit the press and to which the die parts are secured. Since it isdesirable to have the dies in proper alignment with each other one ofthe die set parts is provided with posts that extend toward the otherand that are reclprocable in a bearing in the other part thusmaintaining alignment between the parts.

It will therefore be seen that the die alignment is almost whollydetermined by the fit between the posts or plungers in the bearings.Heretofore one diiiiculty has been to keep the tolerances of these fitsbetween the posts and bearings at a minimum. If the fit was too loosethey could become laterally misaligned and destroy the sharp edges ofthe dies. If the fit was too close, the friction developed during usecaused heating and freezing of the parts making the machine inoperative.Still another disadvantage realized due to loose fitting or worn postswas noticed in the parts that were being formed. Instead of the partshaving sharp clean edges, flash metal or fins appeared around the edgeswhich made necessary subsequent operations of flattening or trimming forthe removal thereof. As a matter of fact, in order to improve theperformance of dies particularly where the metal stock is thin and thearticles small, it has been customary to employ so-called sub presseswhere a line of close manufacture and a refined product is desired and afinished product was to be produced without distorting the metal aroundthe edges.

Still further. these disadvantages were greatly aggravated when thepunching operations are carried out at a high speed. particularly whenthe dies are used with an apparatus such as disclosed in my copendingapplication for Forming machines," Serial No. 497,792, filed August 7,1943.

By my present invention I have made a die set which reduces thetolerance between the pillars or posts and the hearings to a minimum.With a die set employing the improvement of my invention thin as well asthick stock may be stamped or formed with the same die sets; and thesame die sets may be employed throughout long periods of time withoutrebushing.

It is therefore an object of my invention to provide an improved die setfor punch presses or the like.

It is another object of my invention to provide a die set where therewill be no binding or freezing of the parts in spite of the maintenanceof close tolerances.

Another object of my invention is to provide a die set which willprolong the life of the dies.

Another object of my invention is to provide a die set which may beoperated at high speed and still maintain truer alignment than washeretofore possible in the prior art.

Another object of my invention is to provide a die set which can beoperated at high speed and travel laterally with the stock and stillmaintain alignment and avoid the extreme wear entailed in this type ofoperation with die sets of the prior art.

Still another object of my invention is to reduce the friction betweenthe pillars and bearings in die sets.

These and other objects of my invention will become more apparent fromthe following description of some embodiments of the invention whichdescription is illustrated by the accompanying drawings and which formsa part of this specification.

In the drawings:

Fig. 1 is a vertical section taken through the pillars and bearings of adie set employing my invention;

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is an elevatlonal view of a bearing retainer and the bearings inanother form of the invention;

Fig. 4 is a fragmentary perspective of a bearing retainer illustratinganother form of the invention;

Fig. 5 is a diagrammatic view of another form of the invention;

Fig. 6 is a fragmentary section through a bearing showing a fragment ofa pillar in elevation and illustrating another form of my invention;

Fig. '7 is an elevational view of the invention as applied to anothertype oi press. certain hidden parts being shown by dotted lines: and

Fig. 8 is a horizontal section through a pillar, bearing and sleeveillustrating another form of the invention.

Although the invention about to be described is described as used inconnection with punch presses and the formation of sheet metal stock, itis not my intention that the invention shall be limited to the formingof sheet metal only, since it will be clear that it can be used on anytype of machine. where dies having a forming matrix are used to operateon raw or semiiinished stock, to give it a predetermined form.

{Referring now to the drawings throughout which like parts have beendesignated by like reference characters and ilrst particularly to Figs.1 and 2, in Fig. 1, I have illustrated in section a die set embodying myinvention which comprises upper and lower plates l and ii, respectively,which may be adapted for attachment to the traveling cam or slide, andthe bed or bolster oi the press.

The base II is provided with a pair of sleeves ii that may becylindrical in form and each of which is provided with a reduced endportion II having a drive fit in a bore ll in the base. the junction ofthe reduced portion and the body above the base providing a shoulder I!which abuts the top of the plate and assists in maintaining the sleevesin their proper upright position.

The inner surfaces of the sleeves are provided with cylindrical smoothbores II which may be ground and hardened to provide a bearing surfacefor bearings later described.

Depending from the top plate II are pillars or posts the upper ends ofwhich may be split and which are disposed in bores II in the plate andheld therein in any suitable manner, that shown being by plugs 22 whichare driven into the bores of the posts after they are properlypositioned within the bores Ii. These posts are the same in number asthe sleeves. In this instance two are shown, but it is within thepurview of my invention to provide one, three or even more if desired.These posts are arranged to be coaxial with the sleeves and to traveldownward from the position shown to thebottom of the sleeve if desired.

Preferably they may travel down into the cups 28, which are secured tothe lower side of the plate. These cups may be filled with lubricant andthe reciprocation oi the posts into the lubricant forces it up into thebearings. A suitable packing gland I! may be provided at the top of thesleeve which is provided with a packing 29a to prevent loss of thelubricant.

The spaces II and 24, intermediate the posts provide for the receptionof the die parts proper which may be secured on the plates Ill and II inany well known manner.

It will be seen that the posts or pillars III are spaced from the sleevewalls. The surface of these posts are ground and hardened and rolllngelements in the form of balls are inserted between the posts and thesleeve wall. the balls being of a size that causes them to be loadedwhen in position. That is, the balls may be oi a diameter that is atleast equal to the width of the space between the post and the sleeve.It is also desirable to utilize balls that are slightly larger than thisspace. In this event the balls would fit tightly between the walls sothat there would be no lateral movement of the post relative to thesleeve. Balls that are slightly larger than the diameter of the spacewill result in light loading thereof, whereas balls of larger diameterwill result in heavier loading thereof. In this manner die setsembodying the invention can be made where the lateral movement iscontrolled within the desired limit; the loading may be light, medium orheavy, depending upon the character of use for which the die set isintended. It will be understood, however, that it may be desirable touse balls of the same or less diameter in certain instances in whichcase the balls would not be loaded. As shown in Fig. 1 the balls extendin rows around the post, the rows oi balls being in vertically spacedrelation to each other. In the embodiment there are illustrated six suchrows although the size and number of rows is only limited by thediameter of the space between the sleeve and post. Although the postsare shown as having a bore therein, it is within the purview of myinvention to provide posts 0! solid material where desired.

These balls are held in their proper position by a retainer 2 which alsoprevents them from dropping out of position when the post is withdrawnfrom the sleeve to the position illustrated in Fig. 1, since the wallsof the openings that receive the balls extend inward slightly torestrict the size of the opening on the side toward the post as can beseen in the figure.

It should be noted that the balls or retainer do not extend for theentire length of the sleeve. This is because the balls and retainertravel vertically about one half the distance of the movement of thesleeve or post or when both upper and lower plates ill and II are movingequally, the sleeve stands still and the balls rotate.

It will thus be seen that a die set can be constructed according to myinvention wherein the upper and lower parts may be maintained in perfectalignment and that no lateral movement of the parts during use isrealized because oi the loading of the balls between the post andsleeve.

In actual practice for ordinary punch press use the bearing retainer maybe made of metal. however, in connection with the high speed press 01 mycopending application before mentioned, the bearing retainer is alsoformed or Bakelite. synthetic resin, or impregnated wood. This isdesirable because in a device of this character operating at high speed.tightening the retainer decreases the inertia since the dies in thiscase not only travel vertically but sldewise, and helps to prevent theretainer from coming into contact with the walls. The soft material alsodecreases the wear of the parts.

I also dispose the hearings in a single continuous row extending aroundthe post in a spiral or helix form. This is best shown in Fig, 3 whichillustrates a retainer 28a removed from the sleeve.

The retainer for holding the balls may also be formed of a spirallywound strip of material 38 as viewed in Fig. 4 which strip is formedwith upper and lower concave surfaces 8i and the balls are retainedbetween the adiacent convolutions. In the type or a retainer shown inFigs. 3 and 4 there is a tendency for the balls and the retainer torotate around the post in a spiral path thus distributing the wear overa greater area of the post and sleeve.

Although I have shown cylindrical posts and sleeves it is within thepurview of my invention to provide a square or polygonal post and sleevewith equal efllcacy. In this case roller or needle bearings could besubstituted if desired. Also the post and sleeves could be of the formshown in Fig. 5 where the post Illa is elongated in cross section andthe ends are provided with V shaped surfaces III. In this case rollerbearings 4| could be used on each of the surfaces of the V only and nobearings would be necessary on the sides 2 although they could be usedthere if desired. The subject matter of this figure is claimed in myco-pending application Ser. No. 597,321, flied June 2, 1945.

In Fig. 6 I have shown another modification of the invention wherein thewear on the parts is reduced. In this case the post and sleeve areprovided with greater clearance. Disposed adjacent to the posts 20 areballs 60. Next around the balls 60 is disposed a sleeve BI and finallybetween this sleeve and the walls of the bore in the sleeve carried bythe plate H is an additional set of balls 82. Both sets of balls and thesleeve are assembled in loaded condition. During oper ation the balls inthis device only travel about one-half as far as the balls shown in Fig.1, although the relative travel of the upper and lower plates may be thesame. In this manner the life of the balls and other parts isconsiderably prolonged.

In Fig. 7 I have illustrated my invention as applied to forming heads asdescribed in the aforesaid copending application. In this case upper andlower heads III and H are provided. being supported by the eccentricmembers 12. The manner oi operation of the head is fully described insaid application and will not be described here other than to state thateach head travels in a closed circular path in opposite directions thetiming being such that upon their closest approach to each other thematerial disposed between the heads is operated upon. The upper head I0carries two downwardly extending pillars 13 which are secured byscrewing into threaded openings 14 extending through the head, a nut 15locking the same in position.

The lower head supports sleeves II which may be secured in bores in thehead in any suitable manner and the posts 13 extend coaxiall into thesleeves and entirely through the ball retainer 11 with its balls ill.the ends of the posts being provided with collars I9 which may be in theform of a split ring seated in a groove adjacent the end of the post ormounted on a stud screwed into the end of the post. The ends of thesleeves are provided with sumps 8|) the purpose and function of which isthe same as that described for Fig. 1.

It should be noted that the posts I! extend entirely through thebearings and that at no time are they withdrawn therefrom. suchwithdrawal being prevented by the collar 19.

The relative positions and members 01' the posts and sleeves in Figs. 1and 7 may be varied if desired so that the sleeves are carried by thetop head and the posts by the bottom head. Where this is effected thepacking gland 29 keeps the lubricant within the bearing.

In Fig. 8 I have shown a cross section of another type of pillar andsleeve. In this case the sleeve 9| is provided with grooves 92 and thepillar 93 has corresponding grooves 94. The balls 95 are seated in thegrooves being inserted, as in the other modifications, under loadedconditions. The clearance space 96 between the pillar and the sleeve maybe less than in the preceding embodiments. Here the balls always travelin the same path but are provided with a larger bearing surface.

The grooves 92 may extend straight longitudinally in the pillar andsleeve or they may extend spirally. When spiral grooves are provided,for obvious reasons, the grooves on one member should extend spirally tothe right and those on the other should extend spirally to the left.

It will thus be seen that I have provided a die set wherein lateralmovement of the parts is substantially eliminated. This enables the diesto operate on various thicknesses of stock reducing to a minimum thefins or drawn portions normal ly found on stampings and eliminatingsubse quent trimming or shearing operations. Thus it is possible to makemore accurate parts or stampings at a considerable high speed.

Also a die set of this character is particularly useful where themovement of the upper and lower plates is not only toward each other butlaterally where the dies follow the stock as in the case of high speedoperation of the aforesaid application.

Because more accurate alignment of the dies is maintained the life ofthe dies is also materially extended.

Although I have described my invention more particularly as applied todie sets adapted to carry or support dies, it will be obvious to thoseversed in the art that the invention is applicable to these types ofdies where they are not supported on die sets as in the case where thematerial is cut into plates carried by the pillar and bolster itself.

Having thus described my invention I am aware that numerous andextensive departures may be made therefrom without departing from thespirit or scope of the invention.

Iclalm:

1. An apparatus of the class described comprising members adapted forrelative movement toward each other, means to maintain alignment betweenthe members comprising one or more posts carried by the one member andreciprocable in sleeves in the other member and means between the postand sleeves to decrease friction and hold the sleeves and posts againstlateral movement relative to each other.

2. A die set comprising plates adapted for relative movement toward andfrom each other and to support die parts, means for maintainingalignment of the plates with each other comprising posts carried by oneplate and extending in spaced relation to the walls of sockets carriedby the other and anti-friction means disposed in the space between thewalls and posts.

3. An apparatus of the class described comprising members adapted forrelative movement toward and from each other and to support die parts,means for maintaining relative alignment between the members comprisingposts carried by one member and guides carried by the other, said postsextending into said guides in spaced relation to the walls thereof andanti-friction means comprising rolling elements disposed in the spacebetween the walls and posts, said rolling elements being inserted underloaded conditions.

4. A die set comprising plates adapted for relative movement toward andfrom each other and to support die parts, means for maintainingalignment of the plates with each other comprising posts carried by oneplate and extending in spaced relation to the walls of sockets carriedby the other plate and anti-friction means 7 disposed in the spacebetween the walls and posts comprising loaded ball bearings.

5. A die set comprising spaced heads adapted for relative movementtoward and from each other and to support die parts, means formaintaining alignment of the heads with each other comprising postscarried by one head and extending in spaced relation to the walls ofsockets carried by the other head and anti-friction means disposed inthe space between each wall and post, comprising rolling elementsinserted under loaded conditions in said space, and retainers for saidrolling elements spaced from the walls.

6. A die set comprising spaced plates adapted for relative movementtoward and from each other and to support die parts, means formaintaining alignment of the plates with each other comprising postscarried by one plate and extending in spaced relation to the walls ofsockets carried by the other, and anti-friction means disposed in thespace between each socket wall and post, comprising balls inserted underloaded conditions in said space, and retainers for said balls spacedfrom the walls, and comprising a, nonmetaliic sleeve of Bake1ite,"synthetic resin or like material.

'1. A die set comprising spaced plates adapted for relative movementtoward and from each other and to support die parts, means formaintaining alignment of the plates with each other comprising postscarried by one plate and extending in spaced relation to the walls ofsockets carried by the other and anti-friction means disposed in thespace between each wall and post, comprising balls inserted under loadedconditions in said space, and retainers for said balls spaced from thewalls, and comprising a nonmetallic sleeve 01' Bakelite, or syntheticresin, said balls being disposed in spaced rows around said posts.

8. A die set comprising spaced plates adapted for relative movementtoward and from each other and to support die parts, means formaintaining alignment of the plates with each other comprising postscarried by one plate and extending in spaced relation to the walls ofsockets carried by the other and anti-friction means disposed in thespace between the walls and posts, comprising bearings inserted underloaded conditions in said space, said bearings being disposed in spacedrows around said posts.

9. A die set comprising spaced plates adapted for relative movementtoward and from each other and to support die parts, means formaintaining alignment of the plates with each other comprising postscarried by one plate and extending in spaced relation to the walls ofsockets carried by the other and anti-friction means disposed in thespace between the walls and posts, comprising rolling elements insertedunder loaded conditions in said space, and retainers for said rollingelements spaced from the walls, and comprising a non-metallic sleeve of"bakelite," or synthetic resin, said rolling elements being disposed inhelical relation about said post whereby they rotate around the posts ina helical path during reciprocation oi' the posts. I

10. Means for maintaining alignment between the die carrying heads of aforming machine comprising one or more posts carried by one head and oneor more sleeves carried by the other head, said posts extending from theone head coaxially into the sleeves of the other head, and

' 8 loaded bearings interposed between the walls 0 the posts andsleeves.

11. Means for maintaining alignment between the die carrying heads of aforming machine comprising one or more posts carried by one head and oneor more sleeves carried by the other head, said posts extending from theone head coaxially into the sleeves oi the other head, loaded bearingsinterposed between the walls of the posts and sleeves, and a retainerfor holding said bearings against displacement formed of relativelylight anti-friction material.

12. Means for maintaining alignment between the die carrying heads of aforming machine comprising one or more posts carried by one head and oneor more sleeves carried by the other head, said posts extending from theone head coaxially into the sleeves oi the other head, loaded bearingsinterposed between the walls of the posts and sleeves and lubricantretaining means for said sleeve and engaging said posts.

13. Means for maintaining alignment between the die carrying heads oi aforming machine comprising one or more posts carried by one head and oneor more sleeves carried by the other head, said posts extending from theone head coaxially into the sleeves of the other head, loaded bearingsinterposed between the walls of the posts and sleeves, and lubricantretaining means comprising a sump disposed on the end of the sleeveopposite the entering end of the post, and a packing gland on the otherend of the sleeve sealing the sleeve to the post.

14. A die set including spaced plates for supporting parts and adaptedfor movement toward and away from each other, means for maintainingalignment 01' said plates including one or more posts carried by oneplate and one or more sleeves carried by the other plate, said postsadapted to project into said sleeves and means disposed between theposts and sleeves including a ball retainer comprising a helicallyextending member having the adjacent faces of the convolutions of thehelix shaped in concave form to provide a raceway and balls disposed insaid raceway.

15. An apparatus 0! the class described including a pair of die carryingmembers adapted for movement toward and from each other, means formaintaining alignment between said die carrying members and the diescomprising one or more posts carried by one member and sleeves for saidposts carried by the other member, said posts extending and reciprocablein said sleeves and spaced from the walls thereof, and means disposedbetween each post wall and sleeve wall comprising concentric sets ofballs and retainers therefor, and a floating sleeve interposed betweensaid ball sets, said balls and sleeve being inserted in said space underloaded conditions.

16. A die set comprising spaced plates adapted for relative movementtoward and from each other and to support die parts, means formaintaining alignment of the plates with each other comprising postscarried by one plate and extending in spaced relation to the walls ofsockets carried by the other plate, the walls of said posts and socketsbeing formed with helical grooves, and anti-friction means disposed inthe space between the walls and posts in said grooves, comprisingrolling elements inserted under loaded conditions in said space, saidrolling elements being disposed in helical relation about said postwhereby they rotate around the posts in a helical path duringreciprocation of the posts.

17. A die set comprising spaced plates adapted for movement toward andfrom each other with their opposed faces in parallelism, means formaintaining lateral alignment of said plates comprising posts carried byone plate and sleeves carried by the other plate, said posts extendinginto said sleeves in coaxial alignment therewith and provided withlongitudinally extending grooves and balls disposed in said groovesunder loaded conditions.

18. A die set comprising spaced dies adapted for movement toward andfrom each other to stamp, out or press an object to be formed, means formaintaining lateral alignment of said dies in their movement comprisingposts carried by one die and sleeves carried by the other die, saidposts and sleeves provided with helical grooves of opposite inclinationto each othe and balls disposed in said grooves under loaded conditions.

19. An apparatus of the class described comprising members adapted forrelative movement toward each other, means to maintain predeterminedalignment between said members comprising guide means carried by onemember and cooperable with guide means carried by the other member androllin elements disposed between said guide means to decrease frictionresistance and control relative lateral movement therebetween.

20. Means for maintaining in alignment cooperating die means relativelyreciprocable toward and away from each other and adapted to operate onwork disposed therebetween comprising guide means respectively rigidlyconnected with said die means, said guide means having opposed spacedapart guiding surfaces extending parallel to the direction of relativereciprocation of said die means, which surfaces reciprocate in parallelpaths alongside each other upon relative reciprocation of said diesmeans, and mean interposed between said surfaces resisting relativemovement of said guide means in all directions transversely of thedirection of relative reciprocation of said die means.

21. Means for maintaining in alignment cooperating die means relativelyreciprocable toward and away from each other and adapted to operate onwork disposed therebetween comprising guide means respectively rigidlyconnected with said die means, said guide means having opposed spacedapart guiding surfaces extending parallel to the direction of relativereciprocation of said die means, which surfaces reciprocate in parallelpaths alongsid each other upon relative reciprocation of said die means,means interposed between said surfaces and moving relatively to each ofsaid surfaces resisting relative movement of said guide means in alldirections transversely of the direction of relative reciprocation ofsaid die means.

22. Means for maintaining in alignment cooperating die means relativelyreciprocable toward and away from each other and adapted to operate onwork disposed therebetween comprising guide means respectively rigidlyconnected with said die means, said guide means having opposed spacedapart guiding surfaces extending parallel to the direction of relativereciprocation of said die means, which surfaces reciprocate in parallelpaths alongside each other upon relative reciprocation of said diemeans, and anti-friction hearing means interposed between said surfacesand movable relatively to each of said surfaces resisting relativemovement of said guide means in all directions transversely of thedirection of relative reciprocation of said die means.

GUY 0. CONNER REFERENCES CITED The following references are of record inthe file of this patent:

UNITED STATES PATENTS Certificate of Correction Patent No. 2,422,774.

Number Name Date 1,106,564 Hoffmann Aug. 11, 1914 1,568,017 Danly Dec,29, 1925 206,648 Tucker July 30, 1878 1,228,312 Gamier May 29, 19172,026,721 Broulhiet Dec. 31, 1935 2,032,975 Broulhiet Mar. 3, 19362,225,929 Sarozin Dec, 24, 1940 2,316,468 Thomas Apr. 13, 1943 1,603,428Toilefson Oct. 19, 1926 June 24, 1947.

GUY O. CONNER It is hereby certified that error appears in the (printedspecification of the above numbered patent uiring correction as follows:

olumn 10, line 9, claim 21, for

"moving read more la; and that the said Letters Patent should be readwith this correction therein that the same may conform to the record ofthe case in the Patent Signed and sealed this 0th day of January, A. D.1948.

THOMAS F. MURPHY,

Am'ctmt Oommn'uioner of Patents.

for movement toward and from each other with their opposed faces inparallelism, means for maintaining lateral alignment of said platescomprising posts carried by one plate and sleeves carried by the otherplate, said posts extending into said sleeves in coaxial alignmenttherewith and provided with longitudinally extending grooves and ballsdisposed in said grooves under loaded conditions.

18. A die set comprising spaced dies adapted for movement toward andfrom each other to stamp, out or press an object to be formed, means formaintaining lateral alignment of said dies in their movement comprisingposts carried by one die and sleeves carried by the other die, saidposts and sleeves provided with helical grooves of opposite inclinationto each othe and balls disposed in said grooves under loaded conditions.

19. An apparatus of the class described comprising members adapted forrelative movement toward each other, means to maintain predeterminedalignment between said members comprising guide means carried by onemember and cooperable with guide means carried by the other member androllin elements disposed between said guide means to decrease frictionresistance and control relative lateral movement therebetween.

20. Means for maintaining in alignment cooperating die means relativelyreciprocable toward and away from each other and adapted to operate onwork disposed therebetween comprising guide means respectively rigidlyconnected with said die means, said guide means having opposed spacedapart guiding surfaces extending parallel to the direction of relativereciprocation of said die means, which surfaces reciprocate in parallelpaths alongside each other upon relative reciprocation of said diesmeans, and mean interposed between said surfaces resisting relativemovement of said guide means in all directions transversely of thedirection of relative reciprocation of said die means.

21. Means for maintaining in alignment cooperating die means relativelyreciprocable toward and away from each other and adapted to operate onwork disposed therebetween comprising guide means respectively rigidlyconnected with said die means, said guide means having opposed spacedapart guiding surfaces extending parallel to the direction of relativereciprocation of said die means, which surfaces reciprocate in parallelpaths alongsid each other upon relative reciprocation of said die means,means interposed between said surfaces and moving relatively to each ofsaid surfaces resisting relative movement of said guide means in alldirections transversely of the direction of relative reciprocation ofsaid die means.

22. Means for maintaining in alignment cooperating die means relativelyreciprocable toward and away from each other and adapted to operate onwork disposed therebetween comprising guide means respectively rigidlyconnected with said die means, said guide means having opposed spacedapart guiding surfaces extending parallel to the direction of relativereciprocation of said die means, which surfaces reciprocate in parallelpaths alongside each other upon relative reciprocation of said diemeans, and anti-friction hearing means interposed between said surfacesand movable relatively to each of said surfaces resisting relativemovement of said guide means in all directions transversely of thedirection of relative reciprocation of said die means.

GUY 0. CONNER REFERENCES CITED The following references are of record inthe file of this patent:

UNITED STATES PATENTS Certificate of Correction Patent No. 2,422,774.

Number Name Date 1,106,564 Hoffmann Aug. 11, 1914 1,568,017 Danly Dec,29, 1925 206,648 Tucker July 30, 1878 1,228,312 Gamier May 29, 19172,026,721 Broulhiet Dec. 31, 1935 2,032,975 Broulhiet Mar. 3, 19362,225,929 Sarozin Dec, 24, 1940 2,316,468 Thomas Apr. 13, 1943 1,603,428Toilefson Oct. 19, 1926 June 24, 1947.

GUY O. CONNER It is hereby certified that error appears in the (printedspecification of the above numbered patent uiring correction as follows:

olumn 10, line 9, claim 21, for

"moving read more la; and that the said Letters Patent should be readwith this correction therein that the same may conform to the record ofthe case in the Patent Signed and sealed this 0th day of January, A. D.1948.

THOMAS F. MURPHY,

Am'ctmt Oommn'uioner of Patents.

